On Monday night, the palm-tree-lined coast of Samoa looked like paradise. But by early Tuesday morning, residents and tourists alike had an unpleasant awakening. People were literally shaken out of their sleep when a massive earthquake hit 120 miles off the coast of the island, and dozens drowned in the tidal waves that followed. By late morning, the waters had receded, but the nightmare in this remote part of the South Pacific is far from over, as the death toll rises and scattered families try to find their missing relatives.

On Sept. 29 at 6:48 a.m. local time, an earthquake measuring 8.3 on the Richter scale struck midway between Samoa, which is inhabited by 179,000 people, and American Samoa, a U.S. territory with a population of 250,000. Causing nearly 5-yd. (4.5 m) tidal waves that engulfed shores, the events have devastated both Samoan islands, killing at least 119 people, with the death toll expected to rise in the coming days. Most of the damage seems to be in the idyllic south coast of Samoa, a holiday destination for tourists. But there have also been reports of at least six deaths in the nearby Pacific island of Tonga. Houses are destroyed, cars have been swept out to sea and some villages have been virtually annihilated. And an earthquake with a preliminary magnitude of 7.9 has been recorded off the coast of Sumatra in Indonesia. This has resulted in a tsunami warning being issued for Indonesia, India, Thailand and Malaysia. (See pictures of the tsunami striking the South Pacific.)

Wendy Booth, owner of Seabreeze Resort on Upolu Island, told Australian media company Fairfax Radio Network that her hotel had been destroyed by the tsunami. "The second wave hit and came up through the floor, pushed out the back door and threw us outside," she said. "We managed to hang on to a handrail. My husband and I just hung on to each other and the handrail, and then that one [wave] went, but the suckout was tremendous." (See pictures of the Asian tsunami of 2004.)

Sulu Bentley, a Samoan schoolgirl from Leauvaa who was evacuated to Apia, Samoa's capital, told the daily Sydney Morning Herald that she initially thought the tsunami was a prank. "The others were shouting 'Tsunami!' but we thought it's a joke," she said. "But then when we went down [the hill to the markets] on the bus, the police were shouting at us to go to the mountains. And then we saw ... the sea level was high, was rising."

After the Asian tsunami struck on Dec. 26, 2004, killing 230,000 people predominantly from India, Indonesia, Sri Lanka and Thailand in the most devastating tsunami on record, an Indian Ocean tsunami-warning system was launched in 2006. But other local systems, including those covering the Samoas, have been slow to update. "Yes, the region was better prepared as a whole. But Samoa falls under the jurisdiction of the Pacific Ocean Tsunami Warning System," says Jonathan Bathgate, a seismologist from government agency Geoscience Australia. "They are a 50-year-old organization, and their system hasn't changed much in recent years." (Read "Are We Ready for Another Tsunami?")

Some Samoans believe that system failed their relatives today. The Rev. Simeona Taefu from western Sydney told the Australian Broadcasting Corp. that his family was not notified quickly enough. "We've been told only three minutes [before], and then after three minutes, the tsunami came in," he said. "Three minutes is not enough time for people to run away." Bathgate says that in a case like this, the earthquake is the warning. In an island nation, he says, "once the earth shakes, residents should take that as the warning and immediately find higher ground." Residents had roughly an hour to do so, as waves started to hit Samoa's coast at 8 a.m.

Tsunamis are caused by earthquakes, which disrupt the sea floor. In deep oceans they travel unnoticed, but they wreak havoc when they approach shallow water. "This tidal wave happened because of a number of factors," says Bathgate. "The earthquake occurred in an area of the sea where the earth was relatively shallow [20 miles deep], it had a high magnitude and it was close to land."

So far the U.S., Australia and New Zealand have come in with immediate pledges of relief. President Barack Obama declared a disaster for American Samoa and the U.S. Federal Emergency Management Agency has already sent two teams to the region, and two military planes are on standby in Canberra. (Read the U.S. embassy statement.)

Samoan families are also on standby  waiting to hear from missing relatives. A member of the Samoan Methodist Church in Sydney who declined to be named tells TIME that as of Wednesday evening, he still couldn't reach all of his family members. "I got through to some relatives, and they scared. Lots of heartache and sorrow. This was the land they were brought up in," he says. "I jump when the phone rings. I am still waiting for my brother to call."